I feel the same way sometimes. I’m not an expert, but when I make a mistake and start getting down on myself, I try to think about the big picture, and ask myself if my mistake will matter in a year, a month, a week, or even tomorrow. Chances are, nobody will remember it anyway, because your mistakes seem bigger to you than they do to everyone else. Also, when you make a mistake, think of it as a learning experience. As for caring about other people’s opinions, I think if someone really thinks I’m terrible, it’s sad that they’re wasting so much time with negativity towards me when they can’t change who I am. If someone says something mean to you, just take the high road. I’m not sure if this will help but these are some ways I deal with those kinds of feelings.